[Doggie 1]

I've been reading the posts here looking for clues, but I seem to have a problem with my Crdi manual.
I was regularly getting between 1000 & 1100 kms per tank and it has now dropped to around 800-850 km per tank.
Exactly the same driving conditions, exactly the same filling routine, exactly the same fuel (Caltex Vortex) from exactly the same service station.
Nothing has changed except the distance travelled and it has been the same for the last three tanks.
I was just wondering if anyone has any ideas why this could be? I am the only driver.
I had it serviced at 7500 kms, 15,000 kms and then decided that as I do the kms quickly and I am supplying my own top quality oil I would leave the next service til 30,000 kms. I'm currently on 28,000 kms.
Could this have anything to do with it?

I've been reading the posts here looking for clues, but I seem to have a problem with my Crdi manual.
I was regularly getting between 1000 & 1100 kms per tank and it has now dropped to around 800-850 km per tank.
Exactly the same driving conditions, exactly the same filling routine, exactly the same fuel (Caltex Vortex) from exactly the same service station.
Nothing has changed except the distance travelled and it has been the same for the last three tanks.
I was just wondering if anyone has any ideas why this could be? I am the only driver.
I had it serviced at 7500 kms, 15,000 kms and then decided that as I do the kms quickly and I am supplying my own top quality oil I would leave the next service til 30,000 kms. I'm currently on 28,000 kms.
Could this have anything to do with it?

I reckon that's it.  Oil has thickened somewhat. This is normal when using for long oil change intervals - although as long as it's designed for long OCI it would appear to be still fine as a lubricant.

I noticed the reverse effect when I took out my factory fill at ~8,000Km and replaced with Castrol Edge 5w30.  Economy improved immediately and significantly.

The Edge was replaced at 15,000Km with German Castrol 0w30 and I noticed the economy slightly worsened this time and subjectively the engine ran quieter. I remember when I first started the engine after sticking in the Edge that it was a little noisier - which even prompted me to turn it off and recheck the level. At the time I convinced myself I was imagining it all.

Even though the viscosity specification between the two Castrol oils is nearly identical my observations suggest there is significant difference in practice.

I don't propose to try the Edge again!

[Lakes]

db08, i'm getting close to 50,000k but always have oil changed at 7,500. i still get same economy. ask the service stationif there has been changes to the Vortex, as a member has said some Caltex servos have ( could contain up to 2% bio ). you could change the oil, but i think the fuel could have more to do with it.
i've used some of the most expencive oil's money can buy ( but not in my i30), but have never saw a performance gain or power gain. but with fuel's i have seen huge differences. fuel economy can be directly related to power gains or losses. that is if you are driving normally and same as you always have.
have you ever used a fuel aditive ? if not, i would try eather Wynnes Diesel fuel aditive or Chem Tech Diesel Power. i have been useing Diesel Powere when i remember to, for over a year now. the reason i use it is to stop Algea groth in fuel tank. but i wanted to use Wynnes just i could not find it in stock for diesel & the parts guy told me the diesel power was the best, two guy's i work with that have Mercedies Diesels and do a lot of k's used Diesel power but they had no idea if it was helping or not, all the really high k truck owner drivers i know say  they use the Wynnes. if you look back in posts here you will find one from a guy that rarely posted and he had trucks or Bus's he recomended the Wynnes too said they got an economy and performance gain over a period of time useing it on i think bus's. when my bottle of Diesel power is used up i'll try Wynnes too.
let us know how you go, also have you changed the fuel filter yet? i had mine changed at 35,000k. did not notice a gain or loss but just thought i'd mention that too.

[Dazzler]

Hi Dave,

I was wondering how you were..  What does the trip computer say...? (I find mine fairly accurate - imagine yours is mid 6's if your only getting that or you have a fuel leak!!)

I am less than 300km away from 50,000 I did the same as you 7500, 15000, 30000, 45000 and use Castol edge sport 5w30 and use mainly crappy Woolworths Caltex fuel with an occasional tank of BP or Shell..

still sitting on 5.4 l/per100k (combo of city and highway) which means I can easily get 1000 if bother to squeeze in 54 litres or more ..

Hope it gets sorted soon

[Doggie 1]

Thanks everyone for your replies.
I will check re the Vortex and might try fuel from a different outlet. I'll get the service done after the new year and will get the fuel filter replaced.
I'll take a look at that Wynnes product too, it's worth a try.
My trip computer is now showing anywhere from 6.5 to 7, which I haven't had before so something isn't right.

Thanks everyone for your replies.
I will check re the Vortex and might try fuel from a different outlet. I'll get the service done after the new year and will get the fuel filter replaced.
I'll take a look at that Wynnes product too, it's worth a try.
My trip computer is now showing anywhere from 6.5 to 7, which I haven't had before so something isn't right.

You will also have the oil changed. It's still my bet.  Out of interest, what are you using?

[Doggie 1]

Shell Helix Ultra

[I30Racer]

Shell Helix Ultra

Please note that is a directive of Hyundai Europe to use this oil.(for Warranty reson`s)

@db08

Where do you from?

[Doggie 1]

I'm in Perth, Western Australia.
Are you saying it is a directive to use that oil or not to use it?
It has been approved by the Hyundai service centre I use here.

[Lakes]

i'm going to test drive a Ford Fiesta turbo diesel, i know they are a smaller car just they have some possitive idea's that would improve economy, like they are tunned for economy, they have a shift light that lights up when to shift gear for maxium economy ( probably hooked up to engine vacume) they are 10mm lower and use low rolling resistance tyres, also have some wind defectors to cut down wind resistance. they are much taller geared than the i30 so even with five speed there engine rev at a given speed in 5th will  be lower reving than the i30, they make lest power and Torque with same size motor but the power and Torque come in at a lower rev. there combined economy is 3.7l/100k. they use a DPF. the thing i don't like is built in germany, i know german cars are good just every german car i have owned from new, things did not last as long, plus they seem to come with left hand drive in mind so everything like hand brake and so on is toward the left more than the right, also indicator switch is on the left side so when i switch to indicate a lane change or a turn the wippers come on instead i hate that!
but still want to test drive one to compare .

[Dazzler]

i'm going to test drive a Ford Fiesta turbo diesel,

 

I will be interested to hear your findings John.. I don't think you will be switching any time soon ( can imagine it will be very responsive)

[Lakes]

i think we could do the same with an i30, like put low rolling resistance tyres on remove unneeded weight like the tools and spare tyre wheel. lower the car slightly like they have done and fit a shift light that tells you when to shift up and i could see the economy improving on the i30, my ute is lowerred and i saw a gain on my trip computer in economy after lowerering it, but utes have poor wind resistance compared to a car of same tyre.

yes will be interesting to see difference driving the Fiesta

[reecho]

My economy has taken a pounding over the last few weeks mainly due to the AC use, higher outside temps and the build up of lead under my right foot....

[Shambles]

My economy has taken a pounding over the last few weeks mainly due to the AC use, higher outside temps and the build up of lead under my right foot....

... plus the extra weight carrying that recurring squeak around with you

[Dazzler]

I wonder if the ecu has got "out of sorts" might need a re-flash by the dealer at the next srvice..

Hey Dave, is she still nice and torquey..?